CVE-2022-49919 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: release flow rule object from commit path
No need to postpone this to the commit release path, since no packets are walking over this object, this is accessed from control plane only. This helped uncovered UAF triggered by races with the netlink notifier.
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Analysis
by VulDB Data Team • 03/15/2026
The vulnerability identified as CVE-2022-49919 resides within the Linux kernel's netfilter subsystem, specifically within the nf_tables framework that manages packet filtering and manipulation rules. This issue represents a memory management flaw that affects how flow rule objects are handled during the commit phase of rule processing. The vulnerability stems from an improper release timing of flow rule objects that were being delayed in the commit path despite no active packet processing occurring through these objects. The root cause lies in the kernel's control plane logic where flow rule objects are accessed exclusively during administrative operations rather than during active packet forwarding, yet the system was unnecessarily deferring their cleanup to the commit phase where such delays were no longer necessary.
The technical implementation of this flaw demonstrates a classic improper resource management issue that can lead to use-after-free conditions within the kernel's networking subsystem. When netlink notifier events occur concurrently with rule processing operations, the delayed release mechanism creates a race condition that allows for potential memory corruption. The fix addresses this by removing the unnecessary deferral of flow rule object cleanup, ensuring that these objects are released immediately upon completion of their processing rather than being postponed to a later commit phase. This change directly addresses the underlying race condition that was enabling the use-after-free scenario, as the objects are no longer accessible to concurrent operations once their processing is complete. The vulnerability's impact is particularly concerning because it operates at the kernel level where such memory corruption can lead to privilege escalation or system instability.
The operational impact of CVE-2022-49919 extends beyond simple memory management concerns as it represents a potential pathway for attackers to exploit kernel memory corruption vulnerabilities. The race condition created by the delayed release mechanism means that under specific concurrent conditions involving netlink notifications and rule modifications, an attacker could potentially trigger a use-after-free condition that might allow for arbitrary code execution with kernel privileges. This vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software systems, and could potentially map to ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities. The fix directly addresses this by ensuring proper object lifecycle management and eliminating the race condition that was enabling the exploitation path.
Security implications of this vulnerability are significant within enterprise and server environments where netfilter rules are actively managed and where concurrent rule modifications occur. The vulnerability affects systems running Linux kernels with nf_tables functionality, particularly those implementing complex packet filtering policies that rely on netlink communication for rule updates. Organizations should prioritize patching this vulnerability as it represents a potential attack vector for privilege escalation attacks. The resolution addresses the core issue by ensuring that flow rule objects are properly released immediately after processing, eliminating the window of opportunity for race conditions that could lead to memory corruption. This fix contributes to overall system stability and security by preventing potential exploitation scenarios that could compromise kernel memory integrity and lead to unauthorized system access or denial of service conditions.